Allowable nozzle load acc. to API 650

Hi,

By using the flexible nozzle based on API 650 in CAESAR II, the software will calculate the max. allowable (radial force, circumferential & longitudinal moments) please let me know if these allowable loads are calculated according to the API 650-App.P

Thanks in advance

The values you refer to are the limits on the interaction diagrams (the diamond and the triangle) you see in Appendix P. Don't take these values out of context - these are not nozzle limits. They are values used to draw these figures.

Yes these values are computed according to API-650 Appendix P.

Dear Richard,

Actually it is not clear for me. According to the Caesar results the maximum allowed loads are specified. please see below resluts:

----- WRC 297, API-650, & PD 5500 NOZZLES
API-650 NOZZLE NODE = 18
INPUT PARAMETERS:
Tank Diameter ............................. (mm.)= 34186.000
Nozzle Height above bottom plate .......... (mm.)= 635.000
Nozzle Outer Diameter ..................... (mm.)= 609.600
Shell Course Thickness .................... (mm.)= 21.500
Max Fluid Height above bottom plate........ (mm.)= 22044.000
delta Temperature ......................... (C)= 35.000
Modulus of Elasticity ................(N./sq.mm. )= 0.201000E+06
Expansion Coefficient ...............(mm./mm./deg)= 0.500000E-05
Fluid Specific Gravity .................... = 0.860
Reinforcement on (S)hell or (N)ozzle ...... = S
COMPUTED VALUES:
AXIAL TRANSLATIONAL STIFFNESS (N./mm. )= 19158.
LONGITUDINAL BENDING STIFFNESS (N.m./deg )= 159270.
CIRCUMFERENTIAL BENDING STIFFNESS (N.m./deg )= 107002.
RADIAL DEFLECTION DUE TO FLUID & TEMP (mm.)= 14.43
LONGITUDINAL ROTATION DUE TO FLUID & TEMP (deg)= -0.44
MAX ALLOWED RADIAL FORCE (N. )= 23001.
MAX ALLOWED LONGITUDINAL MOMENT (N.m. )= 10980.
MAX ALLOWED CIRCUMFERENTIAL MOMENT (N.m. )= 27086.

pleaes let me know what should I do with these loads

Thank you

Well I made a mistake when I wrote that string into the software. It should really say:

MAX ALLOWED RADIAL FORCE axis limit (N. )= 23001.
MAX ALLOWED LONGITUDINAL MOMENT axis limit (N.m. )= 10980.
MAX ALLOWED CIRCUMFERENTIAL MOMENT axis limit (N.m. )= 27086.


You can't take these numbers out of context. That radial force of 23001 is the maximum, assuming both the longitudinal moment and the circumferential moment are zero. If either is greater than zero, then the radial force can't go as high as 23001. This is why you need those two diagrams.

It is possible that the API 650 nozzle calculations are yielding wrong computed values of stiffness in caesar version 5.10? There is considerable difference between those values and the provided by vendor of the tank.

Caesar II values:

API-650 NOZZLE NODE = 7001
INPUT PARAMETERS:
Tank Diameter ............................. (in.)= 1729.129
Nozzle Height above bottom plate .......... (mm.)= 675.000
Nozzle Outer Diameter ..................... (in.)= 16.000
Shell Course Thickness .................... (mm.)= 25.400
Max Fluid Height above bottom plate........ (mm.)= 16000.000
delta Temperature ......................... (C)= 0.000
Modulus of Elasticity ................(KPa )= 0.200000E+09
Expansion Coefficient ...............(mm./mm./deg)= 0.000000E+00
Fluid Specific Gravity .................... = 0.860
Reinforcement on (S)hell or (N)ozzle ...... = S
COMPUTED VALUES:
AXIAL TRANSLATIONAL STIFFNESS (N./cm. )= 192010.
LONGITUDINAL BENDING STIFFNESS (N.m./deg )= 109525.
CIRCUMFERENTIAL BENDING STIFFNESS (N.m./deg )= 93811.
RADIAL DEFLECTION DUE TO FLUID & TEMP (in.)= 0.42
LONGITUDINAL ROTATION DUE TO FLUID & TEMP (deg)= -0.47
MAX ALLOWED RADIAL FORCE (N. )= 24437.
MAX ALLOWED LONGITUDINAL MOMENT (N.m. )= 10148.
MAX ALLOWED CIRCUMFERENTIAL MOMENT (N.m. )= 59339.


VENDOR VALUES:

AXIAL TRANSLATIONAL STIFFNESS (N./cm. )= 162560.
LONGITUDINAL BENDING STIFFNESS (N.m./deg )= 84347.
CIRCUMFERENTIAL BENDING STIFFNESS (N.m./deg )= 28116.